There are approximately 65.7 million unpaid caregivers in the United States with an estimated 8% providing care to someone with cancer. Although benefit-finding has been reported, providing care to a spouse or loved one with cancer is stressful and can have negative consequences for an individuals psychological and physical health. In cancer caregivers, studies have documented negative outcomes including symptoms of fatigue, impaired sleep quality, poor quality of life, anxiety and depression. These outcomes are of particular concern when cancer patients receive intense treatment such as hematopoietic stem cell transplantation (HSCT) where caregivers are embedded in a treatment trajectory that can extend 4 12 months. Few studies have explored the association among physiological and clinical factors that may affect HSCT caregivers overall risk for cardiovascular disease. While there is evidence indicating that the profound stress experienced by cancer caregivers appears to be associated with autonomic nervous system dysregulation, very little existing evidence suggests that this dysregulation is related to cardiovascular risk. The evidence is lacking even more in transplant caregivers, where no published studies have examined the physiological and behavioral changes that occur in this population over time, nor the cardiovascular risk these individuals face as a result of the overwhelming burden of assisting their loved one through the fear and suffering associated with transplantation. The design of this study was informed from the results of a prior pilot study and phase II study completed at the NIH, Clinical Center. Data from these studies, along with findings from our prior analyses have provided essential information to inform the design of this pilot study which will explore the physiological and clinical markers of chronic stress and cardiovascular risk in a sample of allogeneic HSCT caregivers. The primary objective of this study is to compare physiologic and biomarkers of cardiovascular illness among HSCT caregivers to non-caregivers. A sample of non-caregivers, matched minimally for age, gender, and race/ethnicity are also recruited study participation to serve as study control for each enrolled caregiver subject. The study was approved by the IRB originally on September 30, 2011. Study recruitment began in November 2011; the 1st subject was enrolled in December 2011. The study completed participant accrual in April 2013 and remains open for data analyses only. N=50 subjects (n=26 HSCT caregiver subjects and n=24 matching normal volunteers) have been enrolled with 41 participants (21 caregivers and 20 matching normal volunteers) completing all study procedures. A total of 9 subjects were removed from study (n=5 caregiver subjects and n=4 matching normal volunteers). Each caregiver participant has data collected prior to the transplant recipients HSCT (day 0), during the first week of outpatient visits following the transplant recipients initial discharge from the inpatient setting, and finally 6 weeks post the transplant recipients initial discharge from the hospital. Questionnaires include: Caregiver Reaction Assessment (caregivers only), Health-Promoting Lifestyle Profile II, Perceived Stress Scale, The UCLA Loneliness Scale (Version 3), General Self-Efficacy Scale, and PROMIS Short Forms for Anxiety, Depression, Sleep disturbance and Fatigue. Clinical variables (e.g. vital signs), physiological variables (e.g. cortisol), questionnaires and a medical history and limited physical exam are collected during the clinic visits for both caregiver and matched normal volunteer subjects.